1. Field of the Invention
The present invention relates in general to a presence-based interactive communications system and, in particular, to a presence server and method that can process and integrate the communication preferences of both a presence watcher (or, caller) and a presentity (or, callee) and then distribute the integrated communication preferences to the presence watcher so the presence watcher can make a decision on how to contact the presentity.
2. Description of Related Art
The main function of a presence-based interactive communications system is to improve communications between a presence watcher (or, caller) and a presentity (or, callee). In such a system, the communication efficiency for a specific presence watcher (or, caller) in contacting a specific presentity (or, callee) depends on how much the presence watcher knows about the real-time status of the presentity. For example, the presence watcher may like to know the following information prior to contacting the presentity:
Presence Information:                Availability: Is the presentity available to be contacted?        Activity: What is the current activity of the presentity?        Local Time: Is this the right time to contact to the presentity?        Devices/Media Types: How I can reach the presentity?        More . . . .        
Communication Preferences:                What is the presentity's preferred language?        What is the presentity's preferred device?        What is the presentity's preferred security mode/protocol?        
The presence watcher is also likely to have their own communication preferences. As such, the presence watcher may also like to know the following information:
Can I contact the presentity using my preferred language/device (media type)/security mode (protocol)?
Unfortunately in the traditional presence-based interactive communications system, the presence watcher has no way to get an answer to this last question besides expressing their communication preferences when they send a request to the presentity. This can result in a rejection from the presentity. For a detailed discussion about the traditional presence-based interactive communications system reference is made to the following documents:                Lonnfors, M. et al. “User agent capability presence status extension”, draft-lonnfors-simple-prescaps-ext-02 (work in progress), October 2003.        Rosenberg, J. et al. “Indicating User Agent Capabilities in the Session Initiation Protocol (SIP)”, draft-ietf-sip-callee-caps-01 (work in progress), Oct. 22, 2003.        Rosenberg, J. et al. “Caller Preferences for the Session Initiation Protocol (SIP)”, draft-ietf-sip-callerprefs-10 (work in progress), Oct. 22, 2003.The contents of these documents are incorporated by reference herein.        
As can be seen, the current practice of traditional presence-based interactive communications services is callee-centric: presentities can publish (as a portion of presence information) their communication preferences to their presence watchers and these communications preferences provide value to the presence watchers in making decisions on how the presentity can be contacted. However, no presence-based method exists today that can leverage the communications preferences of the presence watcher such that the communication preferences of the presence watcher are also taken into account along with the communication preferences of the presentity. The lack of such a presence-based method can result in degraded communications satisfaction for the presence watcher. This problem is solved by the present invention.